The board rejected the measure 8-7, reaffirming the current fact-checking system that relies on citizen review panels made up of parents, teachers, and other members of the general public.

The measure was likely proposed in response to a complaint last month, when a Houston mother found her child's newly approved geography textbook referred to African slaves shipped to plantations in the United States between the 1500s and 1800s as "workers."

Instead of requesting academic consultation, the board voted unanimously to require that review panels be made up of "at least a majority" of people with "sufficient content expertise and experience," at the discretion of the Texas education commissioner.

"I think we're making it stronger and better and more expert than in the past," said Marty Rowley, a Republican board member from Amarillo.

Republican board member Thomas Ratliff proposed the initial measure to reduce the national controversy over Texas' textbooks.

"The public perception of our process is not positive and I think we all know that," said Erika Beltran, a Democrat from Dallas.

In 2014, the Texas Freedom Network Education Fund studied new history books up for review by the state's Board of Education. The group highlighted a number of biased inaccuracies, suggesting segregated schools weren't completely bad and Affirmative Action recipients are un-American.

"A number of textbook passages essentially reflect the ideological beliefs of politicians on the state board rather than sound scholarship and factual history," Kathy Miller, the president of the Fund, said in a statement at the time.

After the recent proposal for an enhanced vetting system was voted down Wednesday, Ms. Miller said she is embarrassed for her state.

"With all the controversies that have made textbook adoptions in Texas look like a clown show, it's mindboggling and downright embarrassing that the board voted this down," she said in a statement.

Ellen Rockmore, a writing professor at Dartmouth College, wrote an opinion piece for the New York Times last month suggesting the authors of Texas textbooks structure their sentences to favor slave owners and downplay the horrors of slavery.

"Through grammatical manipulation, the textbook authors obscure the role of slave owners in the institution of slavery," she says. "The textbook publishers were put in a difficult position. They had to teach history to Texas' children without challenging conservative political views that are at odds with history."

Roy White, a veteran of the US Air Force and head of the conservative group called Truth in Texas Textbooks, which participates in the review process, told board members that reviewers had successfully identified numerous errors in the geography book that had sparked the recent controversy and attributed the inclusion of the term "workers" for slaves to inevitable human error.

"You got humans involved, there are going to be some errors," White said.